Method and means for pumping powdered solids



March 25, 1969 D. F. POBST, JR

METHOD AND MEANS FOR PUMPING POWDERED SOLIDS Original Filed July 5, 1966l of 4 Sheet INVENTOR DAVID F. POBST, JR.

ATTORNEY March 25, 1969 D. F. POBST, JR

METHOD AND MEANS FOR PUMPING POWDERED SOLIDS Sheet 2 of 4 Original FiledJuly 5, 1966 mwzw Jon vm mmNCwjmE 0;. h QHE 20m wmjwm Ea INVENTOIR DAVIDF. POBST, JR.

mwesoa wmzwozou ATTORNEY March 25, 1969 D. F. POBST, JR

METHOD AND MEANS FOR PUMPING POWDERED SOLIDS Sheet Original Filed July5, 1966 mmDOI m2; ozTrdmmao b 9 ON on ow r L on wZ \l E F- f. w a 0m om81 $301 m2; QECEEO vm 8 2 N. w w o n 9 8 0m ow on 8 ....Jr 2 2. ow 0m 81INVENTOR DAVID F. POBST, JR.

LINE "c" March 25, 1969 D. F. POBST, JR 3,434,808

METHOD AND MEANS FOR PUMPING POWDERED SOLIDS Original Filed July 5, 1966Sheet 4 of 4 HOURS OPERATING TIME HOURS LINE "I3" FIG.4

OPERATING TIME C) O O O C) O O 0 LO LO 1- r0 NVENTOR DAVID F. POBST,JIR. 3 -8 ammo I-HHO III M 4% ATTORNEYW United States Patent 3,434,808METHOD AND MEANS FOR PUMPING POWDERED SOLIDS David F. Pobst, Jr., Pampa,Tex., assignor to Colombian Carbon Company, New York, N.Y., acorporation of Delaware Continuation of application Ser. No. 562,758,July 5,

1966. This application Dec. 21, 1967, Ser. No. 692,612 Int. Cl. C01b31/14; C09c 1/58 US. Cl. 23-314 21 Claims ABSTRACT OF THE DISCLOSURE Drypowder, such as carbon black, is aspirated into a closed chamber. Theinlet opening is then sealed off, and the powder is positivelydischarged in the opposite direction through a coaxial outlet opening bymechanical displacement. Successive repetition of the aspiration anddischarge steps results in the pumping of the powder from the chamber asa pulsating stream under pressure.

SUMMARY OF THE INVENTION This application is a continuation of Ser. No.562,758 filed July 5, 1966, and now abandoned.

As used herein, the term condensed carbon black powder refers to carbonblack in particulate, flocculent form, the black not being entrained ina gas, as in an aerosol, but having sufficient gas entrained therein torender the powder freely flowing. Condensed carbon black powder is,therefore, distinguished from both powder in the aerosol form andpellets produced by deliberate aggregation of powdered particles.

DETAILED DESCRIPTION OF THE INVENTION Condensed carbon black powdersthat are substantially dry have a moisture content below the amount thatresults in caking or the formation of pastes or slurries of the powder.Such substantially dry, condensed carbon black powders are commonlyproduced during carbon black manufacturing processes when the blackparticles are fractionated from an aerosol within cyclones, bag filtersor other types of suitable separating equipment. After separation, thecondensed powder may be stored in a reservoir, such as a surge tank orstorage bin, prior to packaging or further processing.

The conveying and metering of such substantially dry, condensed carbonblack powder are subject to well-known difficulties. For example, thematerial may bridge in the discharge hopper of a reservoir, thusinterrupting gravitational flow to an outlet through which powder is fedto a meter or conveying apparatus. The maintaining of a constantlycontrolled feed rate is, as a result, difficult to achieve.

To overcome these difficulties, various means such as screw conveyors,variable belt conveyors, and various types of pumps, including a screwtype powder pump, have been used. These means have not been entirelysatisfactory, however, in controlling feed rates. This is due in part tothe constantly changing density of the powder as air is de-entrainedfrom it. It is also due to the tendency of some powders to flow like aliquid when well fluidized or, alternately, to refuse to flow withoutbridging when not fluidized. For these reasons, it has heretofore beennecessary to convert condensed powder to aerosol form prior toconveyance through ordinary pipe. In the condensed state, it could notbe pumped or piped without encountering frequent plugging in the pipingsystem or in the pump itself. The forming and conveying of the aerosolare undesirable due to the need for more costly and elaborate equipmentfor these purposes.

3,434,808 Patented Mar. 25, 1969 It is an object of the presentinvention to provide an improved method and apparatus for pumpingcondensed carbon black powder.

It is another object of this invention to provide a pumping method andapparatus obviating the necessity for converting the condensed carbonblack to aerosol form.

It is another object of this invention to provide a pumping method andapparatus by means of which a constantly con-trolled powder feed ratemay be achieved.

It is a further object of this invention to provide a powder pumpingmethod and apparatus in which the bridging and plugging tendencies ofthe powder are minimized.

With these and other objects in view, the present invention shall bedescribed and claimed hereinafter with respect to the accompanyingdrawings in. which:

FIGURE 1 is a 'vertical cross-section of a pump for conveyingsubstantially dry, condensed carbon black powder;

FIGURE 2 is a diagrammatic view showing an apparatus arrangement for wetpelletizing carbon black powders while employing the pump illustrated inFIGURE 1 as the metering pump for conveying the powder from a surge tankto a wet pelletizing machine;

FIGURE 3 shows plots of liquid feed rate to a wet pelletizing machinevs. time expressed in hours and compares liquid feed rates when usingthe diaphragm pump of FIGURE 1 (Line A) and a helical screw (Line B) asa feeder for carbon black powder;

FIGURE 4 shows plots of pellet temperature as removed from a drum driervs. time expressed in hours of operation and compares temperature whenusing the diaphragm pump of FIGURE 1 (Line C) and a helical screw (LineD) as a feeder for the carbon black powder.

The objects of the present invention are accomplished by aspirating aquantity of substantially dry, condensed carbon black powder into aclosed chamber through an inlet opening in the chamber and thereaftersealing off the chamber inlet opening and discharging the powder as afluid-solid stream through an outlet opening by mechanical displacementmeans that provide forceful and positive discharge of the powder fromthe chamber. The chamber outlet is then sealed off, and another chargeof carbon black powder is aspirated into the chamber. By successivelyrepeating the steps of aspiration and discharge, a pulsating suction canbe provided at the chamber inlet opening for drawing powder into thechamber. Similarly, carbon black in dry, fluid-solid form can bedischarged from the chamber outlet opening as a pulsating stream underpressure. By means of the present invention, a more constant rate ofcarbon black flow has been achieved than is obtainable by previous meansthat are susceptible to bridging of the non-fluidized material andplugging of the feed system. The pulsating suction has a tendency toovercome bridging, as results, for example, when gravity alone is reliedupon to transport the powder from a feed hopper into a conveying system.At the same time, the positive displacement nature of the pump preventsfree flow of highly fluidized material through the pump. Furthermore, ithas been found that the present invention permits the fluid-soliddischarge stream to be conveyed through a surprisingly small piping thatcan be quickly and economically installed.

In one embodiment of this invention, suction and discharge pressures aresupplied to a pumping chamber by means of a material displacement memberarranged to move back and forth in the chamber space. The materialdisplacement member can conveniently be a flexible diaphragm that sealsone end of the closed chamber space and is adapted to flex back andforth in the interior space of the closed chamber. In a preferredarrangement, the chamber inlet and outlet openings for passage ofmaterial are located opposite the internal face of the mechanicaldisplacement member, one of the openings having an annular configurationand the other located centrally with respect thereto.

The method and apparatus of the present invention may be conventientlyadapted to provide pulsating suction and discharge pressures havingessentially reproducible values on each pulse. The invention may thus beused for the volumetric feeding of carbon black powder in processesrequiring an essentially uniform rate of carbon black feed. In the wetpelletizing of carbon black powders, for instance, control over thepelletizing process and the quality of the resulting pellets is greatlyenhanced by means of the present invention.

In order to more fully describe the present invention, an embodimentthereof is hereinafter described with reference to the accompanyingdrawings. In FIGURE 1, a closed pump chamber 1 is bounded by theinternal wall 2 of a cylindrical pump casing 3, the internal face of thematerial displacement member 4, and the top surfaces of flexible ring 5associated with the inlet valve 7 and seal disc 6 associated with theoutlet valve 8.

The displacement member represented at 4 consists of a flexible rubberdiaphragm 9, plunger plate 10 and clamp 11. Plunger plate 10 and clamp11 are fastened together with bolts 12 and securely grip the diaphragm 9to permit flexure thereof by up and down movement of the plunger rod 13.The peripheral edge of the diaphragm is tightly fastened to a registersurface 14 of the pump casing 3 by clamp ring 15 compressed by clampingbars 16 and the associated bolts 17 screwed into receptacles 18 that areattached to pump casing 3.

Beneath the pump chamber 1 is an annular material inlet passage 19bounded by an inner cylinder 20, an outer cylinder 21, and a floor piece22. Material drawn into the pump enters the annular passage 19 throughconduit 23 and subsequently passes through the inlet valve, representedat 7, into the pump chamber 1. Centrally located within the annularmaterial inlet passage .19 is a material outlet passage 24 bounded bythe internal wall of the inner cylinder '20 and end piece 25. Materialbeing discharged from the pump leaves chamber 1, passes through theoutlet valve represented at 8, enters the outlet chamber 24, andsubsequently leaves the pump through conduit 26.

The inlet valve represented at 7 is essentially a checkvalve andconsists of a flexible ring 5, suitably made of rubber, a ring-shapedseat 27 and a ring-shaped seal 28. The internal edge of the flexiblering is clamped in position over the cylindrical inner wall by means ofclamp ring 29 and associated bolts 30. The ring-shaped seat 27 isfastened to the lower surface of flexible ring 5 by means of a clampingring 31 and associated bolts 32. The ringshaped seal 28 is locatedbeneath the ring-shaped seat 27 for complete uniform contact between theopposing surfaces of each when the inlet valve is closed. When arrangedas shown in the drawing, the inlet valve opens when the materialdisplacement member 4 is raised sharply upwards away from the flexiblering 5, thus creating a suction in chamber 1. The higher pressure in theannular inlet 19 forces the flexible ring 5 to flex upward lifting seat27 from seal 28, thus creating an inlet opening into pump chamber 1.Since the seat and seal are ring-shaped, the inlet opening extends allthe way around the bottom of pumping chamber 1 and, therefore, has anannular configuration. Inlet valve 7 is closed when the pressure in thechamber 1 is greater than that in inlet passage 19 or when no pressuredifferential exists between those two spaces. Therefore, valve 7 closeswhen the material displacement member is moved downward toward flexiblering 5, and the valve remains closed when the displacement member is atrest.

The outlet valve represented at 8 is also essentially a check-valve andconsists of a seal 6, a circular seat 33, a backing disc 34 having aspring mount 35, a spring 36,

and a spring seat 37 attached to a spring compression adjustment rod 38arranged for axial movement through a guide 39. The circular seat 33 islocated around a center opening in a rigid ring-shaped plate 40 boltedonto cylinder 20 by means of clamping ring 29 and bolts 30. The sealdisc 6 is maintained rigid by means of the backing disc 34 and isattached thereto by bolts and washers 41. In the arrangement shown inthe drawing, the outlet valve opens when the material displacementmember is moved downward toward the seal disc 6, thus creating apressure in chamber 1. As a result, seal disc 6 of the outlet valve isdisplaced from contact with seat 33 when the pressure in pump chamber 1is greater than the compressive force of the spring 36 urging seal disc6 upward, thus creating an outlet opening between seal disc 6 and seat33 for passage of material out of chamber 1. The outlet valve closeswhen the material displacement member is moved away from seal disc 6,thus creating a vacuum in chamber 1 since the seal disc is urged intocontact with seat 33 by the spring 36. Furthermore, the outlet valveremains closed when the material displacement member is at rest.

Prefereably the aforementioned seats and seals are provided with flatcontacting surface having an annular crosssection. The seats arepreferably provided with a tapered side wall extending away from theseal contacting surfaces. Ideally, the seal-contacting surfaces of theseats have a cross-sectional configuration of a thin ring, since thetendency for carbon black to cake on the contacting surfaces is greatlyreduced by minimizing their area of contact. Suitable seats and sealsmay be made of hard metal and rubber, respectively, but it will beunderstood that other designs and materials of construction may beemployed.

In order to optimize pumping efliciency, the pressure employed to seatseal disc 6 may be regulated by adjusting the compression of spring 36.This may be accomplished by turning the adjustment rod 38 in nut 42,which is aflixed to the end plate 25, thereby moving the spring seat 37up or down and thereby adjusting the compression on spring 36 so thatthe amount of pressure required to unseat the seal disc iscorrespondingly altered. Once the compression of the spring is properlyadjusted further movement of the rod 39 is prevented by tightening locknut 43 against nut 42.

When pumping carbol black powders of certain types, it is sometimesbeneficial to introduce small amounts of a nonreactive gas into theinterior of the pump either intermittently or continuously. In the pumpshown in FIGURE 1, the gas may be fed in through conduit 44 whichsupplies a ring 45 having a series of exhaust openings 46. Introductionof the nonreactive gas into the pump is intended to render the carbonblack powder more fluid without forming an aerosol, or the gas may beintroduced intermittently but forcefully in order to clean the inlet andoutlet valves of deposits which may cake thereon.

To operate the pump, the plunger rod 13 is moved up and down through apre-established distance at a constant rate with a suitable drive means,not shown. This results in flexure of diaphragm 9 so that the materialdisplacement member moves back and forth within the pump chamber 1 toproduce, alternately, vacuum and pressure within the chamber. Since thestroke of the material displacement member is constant during eachpumping cycle, the vacuum and pressure produced within the pump chamher1 is reproducible from one cycle to the next. Where desired, means maybe employed for re-establishing the pumping cycle rate or the length ofstroke, and since such means will be apparent to one skilled in the art,they need not be described herein.

In accordance with FIGURE 1, powder is aspirated into the pump when thematerial displacement member is moved upwards. Conduit 23 isinterconnected with a reservoir for the powder, and upon creating avacuum within chamber 1, inlet valve 7 opens and a quantity of thepowder is pulled into the chamber,

As the cycle continues, the material displacement member moves downward,outlet valve 8 is forced open by pressure created within chamber 1. Atthe same time, inlet valve 7 closes to prevent reversal of flow out ofthe inlet opening. Continued downward movement of the materialdisplacement member holds the outlet valve open so that material isdischarged from the chamber outlet opening into outlet chamber 24 andfinally passes out conduit 26 which interconnects with a point ofdelivery for the powder. When the material displacement member movesupward, the outlet valve closes and remains closed until the chamber isagain pressurized, thus preventing reversal of flow through the chamberoutlet opening.

It will be apparent that successively repeated in and out movement ofthe material displacement member results in a pulsating suction at thepump inlet, and a pulsating discharge at the pump outlet, thus effectinga pulsating pumping action. The resulting pulsating flow of powder toand from the pump is highly beneficial in overcoming plugging orbridging which could interrupt the pumping operation. The pulsationsproduced provide an effect akin to vibration that is created by repeatedinterruption of suction and discharge pressures.

Flow of powder through the pump itself is greatly facilitated byarrangement of the inlet and outlet openings in accordance withFIGURE 1. It can be seen that powder enters the pumping chamber axially,in respect to movement of the material displacement member, and thenleaves the chamber axially in the opposite direction without having totravel from one side of the pump chamber to the other beneath thediaphragm. Placement of the chamber inlet and outlet openings oppositethe face of the material displacement member, while locating one openingcentrally of the other, minimizes lateral movement of the powder duringtransit through the pump. This placement at the same time permits bothopenings to have a maximum size in respect to the displacement memberemployed. In the pump illustrated in FIGURE 1, the inlet and outletopenings are located coaxially and centered opposite the point ofmaximum flexure of the diaphragm. Since the outlet is centrally located,powder may be discharged through the outlet while minimizing lateraldisplacement of the powder.

Although the illustrated pump has an annular chamber inlet with anoutlet located centrally thereof, it will be understood that thisarrangement can be reversed by suitable revision of the valves.Furthermore, the material displacement member need not necessarilyconsist essentially of a diaphragm as herein described, but may consistof a piston, bellows or the like.

The carbon black pumping rate is determined, of course, by a number offactors subject to variation. These include the size of the pump, speedof cycling and length of the stroke. When desired, the discharge streamsfrom two or more pumps may be joined together to increase the rate ofmaterial flow.

FIGURE 2 is a diagram illustrating a wet pelleting process forconverting carbon black powders into pellets, wherein the pump of FIGURE1 is employed for conveying a metered stream of condensed carbon blackpowder from a surge tank to a wet pelletizing machine. Carbon blackpowder that has been freshly condensed from an aerosol is fed into aprocess surge tank 47 through conduit 48. Within the tank, the drypowder is slowly stirred with agitating members 49, mounted on arotating shaft 50, to promote settling of the powder. Pump 51, havingdrive means represented at 51a, is interconnected with tank 47 and a wetpelletizing machine, represented at 52, through an inlet conduit 53 anda discharge conduit 54. Wet pellets formed in the pelletizing machineare passed through conduit 55 into a pellet polisher 56 and subsequentlyinto a drier, generally represented at 57, through conduit 58. Driedpellets are removed from the drier through discharge spout 59.

The wet pelletizing machine 52 consists essentially of an elongatedconduit 60 having an axially mounted shaft 61 rotated by drive means,represented at 62, and provided with agitating members 63 which projectradially from the shaft. A metered stream of liquid feed, e.g. water,oil, or an aqueous solution of [binder for the powder particles, is fedinto conduit 60 through line 64. Metered streams of carbon black powderand liquid are thus fed into the wet pelletizer at carefullyproportioned rates which result in pellets having a desired size, shape,and liquid content when the mixture of powder and liquid are subjectedto agitation within conduit 60. Variations in feed rate of powder orliquid may result in pellets having improper shape or size, dusting outor mudding out of the pelletizer, or overloading of the drier due toexcessive liquid content of the pellets.

Within the polisher 56, the wet pellets are subjected to additionalagitation for further rounding and smoothing thereof. Construction ofthe polisher is akin to that of the wet pelletizing machine, since itlikewise consists essentially of an elongated conduit 65 that housesagitating members 66 affixed to a rotating shaft 67 and extend radiallytherefrom, the shaft being rotated with a drive means represented at 68.

The drier represented at 57 is employed for removal of liquidincorporated into the pellets during formation, but undesirable in thefinished product. A horizontally elongated rotating drum 69 is heatedexternally by means of hot gases generated by burners 70. The drum 69 isenclosed with an insulated shell 71 which directs the flow of hot gasesaround and in contact with the surface of the drum before passing out ofexhaust stack 72. The lefthand end of the drum is sealed with a hood 73having the pellet discharge spout 59 and an inlet conduit 74 forintroducing purge gases through the interior of the drum. The right-handend of the drum is sealed with another hood 75 having an outlet throughwhich liquid vapors and purge gases are removed from the interior of thedrum during the drying operation.

In the wet pelletizing machine 52, the carbon black powder and wettingliquid are subjected to agitation by bars 63 as the wetted powder massadvances axially from left to right. Ideally, the rotational speed ofthe shaft 61 and the feed rates of both powder and liquid are all heldconstant, for when such is the case, little or no variation occurs inthe quality of the wet pellets once optimum conditions have beenestablished. In practice, however, control of the powder feed rate hasproven very difficult because of problems with bridging, plugging andvariation in bulk density of the powder. Frequent adjustments in liquidfeed rate were necessary to compensate for fluctuations in powder feedrate since the latter resulted in consequential variations in pelletquality. In accord ance with the present invention, the pump of FIGURE 1may be employed as a metering pump for the carbon black feed streampassed into the wet pelletizer, and when such is the case, regulation ofthe liquid feed rate may be substantially reduced in degree andfrequency, thus providing pellets of higher quality.

Example Substantially dry, freshly condensed car-bon black (ISAF grade)was conveyed from a surge tank to a wet pelletizing machinesubstantially in accordance with the process as shown in FIGURE 2 exceptthat two pumps, arranged in parallel, were employed instead of one.

Each pump was constructed substantially in accordance with FIGURE 1,having an internal chamber diameter of 11 inches, annular material inletpassage of 5%" ID. x 9%" OD. and a cylindrical material outlet passageof 4 /2" diameter. The outside diameter of the inlet valve seat was 10inches, and the inside diameter of the outlet valve seat was 3 inches.Inside diameter of the inlet and outlet conduits, at the pump, was 2inches. The total distance over which the diaphragm was flexed back andforth within the pump chamber space (stroke) was 3 inches. The operatingspeed of the pump was 90 cycles per minute, which effected a carbonblack pumping rate of approximately 2,290 lbs/hr. for the two pumps. Airwas fed into the pump for aeration of the carbon black powder at therate of about 2 s.c.f.m.

From the pump, the fluid-solid stream of carbon black was conveyedthrough 60 feet of 2 inch I.D. flexible pipe to a wet pelletizingmachine into which an aqueous solution of binder material was alsointroduced at the rate of 335 gallons per hour. Within the wetpelletizing machine the carbon black powder and binder solution weremixed together under agitation to form wet pellets which weresubsequently polished and dried to produce dry pellets having a moisturecontent not exceeding 1% by weight.

It can be seen from Line A of FIGURE 3 that almost no regulation intheflow rate of the aqueous solution of the binder fed into the wetpelletizing machine was required over a 24 hour operating period. Line Bshows the amount of regulation required when attempting to maintain thesame feed rates for carbon black powder and liquid to the pelletizingmachine when employing a helical screw as a feeder for the powder. Itwas not possible to maintain a constant powder feed rate with this screwfeeder because of variations in bulk density and bridging in the feedhopper. Consequently, variations in the powder feed rate required thatthe liquid rate be frequently adjusted in attempt to maintain pelletquality.

In a like manner, Line C of FIGURE 4 shows the temperature of pelletsbeing removed from the outlet of the drier during the same 24 hourperiod when using the diaphragm pump as a powder feeder for thepelletizer, while Line D shows the temperature of the pellets at theoutlet when using the screw feeder mentioned above. In the drying ofcarbon black pellets, quality is influenced by drying temperature, i.e.the surface chemistry of the carbon black particles may be altered byexcessive drying temperatures or substantial fluctuations therein. Sincethese surface chemistry eflects markedly influence the performance ofcompounds in which the black is incorporated, adequate control of dryingtemperature is very important. Comparison of Lines C and D indicate thatmore desirable drying conditions existed when employing the diaphragmpump as the powder feeder for the pelletizing machine since a generallylower temperature of drying was maintained, with less fluctuation thanwas experienced when using the helical screw as the powder feeder.

While the invention has been described herein with reference toparticular embodiments thereof, it will be readily apparent to thoseskilled in the art that various changes and modifications can be madetherein within the scope of the invention as set forth in the appendedclaims.

I claim:

1. In a process for treating carbon black, the method of feeding thecarbon black as an essentially dry, condensed powder at a uniformpredetermined rate comprising:

(a) aspirating a quantity of substantially dry, condensed carbon blackpowder through an inlet into a closed chamber by means of a vacuumimposed therein by the movement of a mechanical displacement member inone direction within said closed chamber;

(b) sealing off said inlet and discharging the carbon black powder fromsaid closed chamber by means of positive pressure created by movement ofthe mechanical displacement member through said closed chamber in theopposite direction;

(c) thereafter aspirating another quantity of powder into said chamberand successively repeating the steps of aspirating and dischargingpowder from said closed chamber;

(d) passing the discharged powder as a pulsating stream of dry carbonblack powder into a treating Zone requiring input of said carbon blackpowder at a predetermined rate, whereby a pulsating action is providedthat tends to break the bridging of nonfluidized carbon black and alsoprovides a pulsating, flowing stream of condensed carbon black powderthrough the system so that a relatively uniform, predetermined rate offlow into said treating zone is maintained.

2. In a feed system for transporting essentially dry, condensed carbonblack powder, pumping means resulting in improved carbon black flow ratecharacteristics and reduced tendency of the carbon black to plug thefeed system comprising:

(a) a closed chamber having an inlet opening adapted to receive carbonblack powder and an outlet opening adapted to discharge carbon blackpowder from the closed chamber, one of said openings having an annularconfiguration and the other [being located centrally with respectthereto;

(b) a material displacement member adapted to move back and forth in theinterior space of said chamber, the internal face of said membercomprising one end of said closed chamber;

(c) means for opening the chamber opening having an annularconfiguration when said material displacement member is moved in onedirection within said chamber and for closing said opening when saidmaterial displacement member is moved in the opposite direction withinsaid chamber, said means comprising:

(1) a ring-shaped seal around the chamber opening having an annularconfiguration,

(2) a flexible ring adapted to flex back and forth in the same relationas said material displacement member,

(3) a. ring-shaped seat mounted on said flexible ring, said ring-shapedseat being displaced from contact with the ring-shaped seal by flexureof the flexible ring when said material displacement member is moved inone direction, and said ring-shaped seat being in contact with thering-shaped seal when said material displacement member is moved in theopposite direction,

(d) means for opening said chamber opening located centrally withrespect to the opening having an annular configuration when saidmaterial displacement member is moved in a direction so as to close saidopening having an annular configuration and for closing said chamberopening when said material displacement member is moved in a directionso as to open the chamber opening having an annular configuration,

whereby movement of said material displacement member in one directioncreates a suction within said chamber capable of aspirating a quantityof condensed carbon black powder into the interior space of said chamberand movement of said material displacement member in the oppositedirection creates a pressure within said chamber capable of dischargingsaid carbon black powder from said chamber, said back and forth movementof said material displacement member thereby being capable of achievinga relatively uniform pulsing flow of condensed carbon black powderthrough the feed system with minimum bridging of said powder andplugging of said feed system.

3. The apparatus of claim 2 in which the material displacement member isa flexible diaphragm.

4. The apparatus of claim 2 and including a wet pelletizing apparatus incommunication with the discharge opening of said pumping means, saidpelletizing apparatus comprising an elongated conduct having a feedinlet for said carbon black powder and a discharge outlet for wet carbonblack pellets, a rotatable shaft running axially through said elongatedconduit, agitating members aflixed to said rotatable shaft, means forrotating said shaft, and a means for introducing a stream of liquid intosaid elongated conduit.

5. The apparatus of claim 2 in which said inlet and outlet openings arelocated opposite said internal face of the material displacement member.

6. The apparatus of claim 2 in which the means for opening and closingthe chamber opening located centrally with respect to the opening havingan annular configuration comprises:

(a) a circular seat around said centrally positioned opening for thepassage of carbon black,

(lb) a seal disc that engages said seat, said seal disc being in contactwith said circular seat when the material displacement member is movedin one direction and said seal disc being displaced from contact withsaid circular seat when said material displacement member is moved inthe opposite direction.

7. The apparatus of claim 6 in which the opening having an annularconfiguration is an inlet through which material is drawn into theclosed chamber and the ringshaped seat is displaced from contact withthe ring-shaped seal by movement of the material displacement memberaway from said flexible ring. t

8. The apparatus of claim 7 in which the centrally positioned opening isan outlet through which material is discharged from the chamber, thedisc seal being displaced from contact with the circular seat bymovement of the material displacement member toward the disc seal.

9. The apparatus of claim 8 in which the disc seal and the ring-shapedseat are arranged for linear axial movement in relation to theirrespective seat and seal.

10. The apparatus of claim 8 and including spring means urging the sealdisc into contact with said circular seat.

141. The apparatus of claim 10 and including means for adjusting thecompressive force provided by said spring.

12. The apparatus of claim 8 in which the valve seals have flat facesfor contact with said seat and the sealcontacting surfaces of the valveseats are flat and have the cross-sectional configuration of a thinring.

13. The apparatus of claim 8 in which the closed chamber outlet emptiesaxially into a confined space having a diameter significantly greaterthan the seat and seal of the outlet valve.

14. The apparatus of claim 13 in which material is supplied to the inletopening through a second confined space surrounding said axial confineddischarge space.

15. A method of pumping condensed carbon [black powder in which improvedflow rate characteristics and reduced tendency for plugging of the flowsystem are obtained comprising:

(1) aspirating a quantity of substantially dry, condensed carbon blackpowder through an inlet into a closed chamber by means of a vacuumimposed therein by the movement of a mechanical displacement member inone direction within said closed chamber;

(2) sealing off said inlet and discharging the carbon black from saidclosed chamber coaxially but in the opposite direction to the flow ofcarbon black into the closed chamber by means of positive pressurecreated by the movement of the mechanical displacement member throughsaid closed chamber in the opposite direction, and

(3) thereafter aspirating another quantity of carbon black powder intosaid chamber and successively repeating the steps of aspirating anddischarging powder from said closed chamber,

whereby a pulsating suction is provided that tends to break the bridgingof non-fluidized material and also provides a pulsating, flowing streamof condensed carbon black powder that tends to prevent the free flow ofhighly fluidized material through the system so that a relativelyuniform rate of flow can be obtained.

16. The method of claim 15 in which the pulsating stream of dry powderis passed into a continuous process requiring input of said powder at anessentially constant rate.

17. The method of claim 16 in which said continuous process requiringinput of powder at an essentially constant rate is a wet pelletizingprocess for converting carbon black powder into beads.

18. The method of claim 15 and including the mixing of a non-reactivegas with the carbon black powder within said closed chamber, therebyaerating the powder before it is discharged from said chamber.

.19. The method of claim 15 in which said aspirating into anddischarging of the carbon black powder from said closed chamber areaccomplished by flexing a diaphragm back and forth within the closedchamber, a suction being created within said chamber when said diaphragmis flexed in the opposite direction, the flexure of said diaphragm backand forth thereby causing the pumping of said carbon black powder.

20. In a wet pelletizing process for forming beads from carbon blackpowder, the method of feeding the carbon black powder into thepelletizing zone at a uniform, predetermined rate comprising:

(a) aspirating a quantity of substantially dry, condensed carbon blackpowder through an inlet into a closed chamber by means of a vacuumimposed therein by the movement of a mechanical displacement member inone direction within said closed chamber;

(b) sealing off said inlet and discharging the carbon black powder fromsaid closed chamber by means of a positive pressure created by movementof the mechanical displacement member through said closed chamber in theopposite direction;

(c) thereafter aspirating another quantity of carbon black powder intosaid chamber and successively repeating the steps of aspirating anddischarging powder from said closed chamber;

((1) passing the discharged carbon black powder as a pulsating stream ofdry powder into a wet pelletizing zone wherein the canbon black powderis converted into pellets, said wet pelletizing zone requiring input ofcarbon black powder at a predetermined rate;

whereby a pulsating action is provided that tends to break the bridgingof non-fluidized carbon black powder and also, provides a pulsating,flowing stream of condensed carbon black powder through the system sothat a relatively uniform, predetermined rate of flow of said powderinto the wet pelletizing zone is maintained.

21. Apparatus for pelletizing carbon black comprising:

(a) an elongated conduit having a feed inlet for essentially dry,condensed carbon black powder and a discharge outlet for wet pellets ofsaid powder which are formed within the conduit;

(b) a shaft axially mounted within said conduit and rotatable therein;

(c) a series of powder-agitating members which extend radially outwardfrom the shaft;

(d) means for introducing a stream of liquid into said conduit at apredetermined rate;

(e) a closed chamber having an inlet opening adapted to receiveessentially dry, condensed carbon black powder and an outlet openingadapted to discharge said powder from the closed chamber to said elongated conduit;

(f) a material displacement member adapted to move back and forth in theinterior space of said chamber;

(g) means for opening the chamber inlet when the material displacementmember is moved in one direction within said chamber and for closingsaid opening when said material displacement member is moved in theopposite direction within said chamber; and

(h) means for opening said chamber outlet when said materialdispla-cement 'member is moved in a direction so as to close saidchamber inlet and for closing said chamber outlet when said materialdisplacement member is moved in a direction so as to open said chamberinlet;

whereby movement of said material displacement member in one directioncreates a suction within said chamber capable of aspirating a quantityof essentially dry powder into the interior space of said chamber andmovement in the opposite direction creates a pressure within saidchamber capable of discharging said powder from said chamber into saidelongated conduit, said back and forth movement of said materialdisplacement member thereby achieving a relatively uniform pulsatingflow of the essentially dry, condensed carbon black powder into saidelongated conduit with minimum bridging of said powder and plugging ofthe system.

References Cited UNITED STATES PATENTS ANDRES H. NIELSEN, PrimaryExaminer.

US. Cl. X.R.

@3 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,6 1 ,808 Dated March 25. 1963 Inventor(5) David F- PObSt, JI'.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

I' Column 10, Claim 19 should appear as follows "'1 19. The method ofClaim 15 in which said aspirating into and discharging of the carbonblack powder from said closed chamber are accomplished by flexing adiaphragm back and forth within the closed chamber, a suction beingcreated within said chamber when said diaphragm is flexed in onedirection, and a pressure being created within said chamber when saiddiaphragm is flexed in the opposite direction, the flexure of saiddiaphragm back and forth thereby causing the pumping of said carbonblack powder.

SIGNED AND SEALED MAR 1 71970 (SEAL) Atteat:

EdwardlLFletchmIr.

mm B- SCIHUYLER, In. Attesting Officer Oomissioner of Patents

